Mobile Communication Systemsy

Part 1- Introduction & Principles

Professor Z GhassemlooyProfessor Z Ghassemlooy

School of Computing, Engineering and Information Sciences

School of Computing, Engineering and Information Sciences

University of NorthumbriaU.K.

University of NorthumbriaU.K.

Prof. Z. Ghssemlooy

http://soe.unn.ac.uk/ocrhttp://soe.unn.ac.uk/ocr

Reading List

- Mobile and Data Communications Systems, D Wong, D Britland, Pub: Artech Housey , g, ,- Mobile Communications, A Jagoda, M DeVillepin, Pub: J. Wiley- Mobile Information Systems, Editor: J. Walker, Pub: Artech House- Introduction to Digital Mobile Communications, Y Akaiwa, Pub: J. Wiley

Mobile Communications 2nd Ed J Schiller ISBN 0 321 12381 6- Mobile Communications, 2nd Ed, J Schiller, ISBN 0-321-12381-6 - Wireless Communications & Networks – Stallings - Mobile Communications – Dr. J. Schiller- 3G Wireless Demystified - Hartey-Introduction to Telecommunications - Anu Gokhale - Mobile Communication Systems, Parsons J D and Gardiner J G, Blackie USA Halsted Press

Mobile Communications Engineering Lee William C Y McGraw Hill Inc- Mobile Communications Engineering, Lee, William C. Y., McGraw-Hill, Inc. - Mobile Cellular Telecommunications Systems, Lee, William C. Y., McGraw-Hill, Inc.

Websites:Websites:- IEC Online Education- How Stuff works- Teracom Training Institute

Prof. Z. Ghssemlooy

g- Telecom Writing

Contents

Frequency BandHistory Part IyPrinciplesTransmission PropertiesTransmission PropertiesCellular ConceptT ffi E i iTraffic Engineering Propagation ModulationPerformance

Prof. Z. Ghssemlooy

Frequency Bandsq y

VHF (30 MH 300 MH )VHF (30 MHz - 300 MHz)

VHF Mid B d (70 87 5 MH )– VHF Mid Band (70 - 87.5 MHz)– VHF High Band (148 - 174 MHz)

UHF (300 MHz - 3 GHz)

– UHF Band (403 - 420 MHz)– UHF Band (450 - 520 MHz)UHF Band (450 520 MHz)– UHF Band 900 MHz (820 - 960 MHz) ⎫– UHF Band 1.9 GHz (1880 - 1900 MHz) ⎫

Prof. Z. Ghssemlooy

( )

Mobile Services

Private Mobile Radio (PMR) System ⎫ate ob e ad o ( ) Syste ⎫– Conventional Mobile Radio Systems

• Simple two-way radio• Fixed frequency assignment• Fixed frequency assignment• Generally no privacy

– Trunked Mobile Radio SystemsC ll l t k hit t• Cellular network architecture

• Efficient use of the frequency spectrum• Intelligent radio equipment

Cordless Telephone Systems (e.g. DECT)– Analogue Cellular Phone Systemsg y– Digital Cellular Phone Systems ⎫– Personal Communication Systems

Prof. Z. Ghssemlooy

– Mobile Data Services

Mobile Communications - Historyy

1934 AM based: 1st Generation Analogue Cellular Systems1934-USA

AM based: 1st Generation Analogue Cellular Systems- For public safety- 5000 mobiles - Vehicle ignition noise a major problem

1935 USAE

FM based: - Frequency bands:- 800 - 900 MHz and 400 - 500 MHz - 120 kHz RF bandwidth channel spacing of 30 kHzEurope

Asia- 120 kHz RF bandwidth, channel spacing of 30 kHz- Data rate 5 - 10 kbps- No of channels 400 – 1000, half-duplex

1946-USA

First Generation Public Mobile Telephone Service:- Coverage distance: 50 km, 60 kHz bandwidth

Prof. Z. Ghssemlooy

- Single powerful transmitter

History - 1st Generation (1G) Systemsy ( ) y

1960 Cellular Radio, developed by Bell Labs., p y

19 0 C ll l M bil S t (USA)1970 Cellular Mobile System (USA)

1980 First Generation Analogue Cellular Systems

- Advanced Mobile Telephone Systems (AMPS)- Advanced Mobile Telephone Systems (AMPS)- Frequency bands: 800 - 900 MHz and 400 - 500 MHz

Ch l i 30 kH d f h l 400- Channel spacing 30 kHz and no of channels 400 – 1000

- Data rate 5 - 10 kbps

Prof. Z. Ghssemlooy

p-FM for speech, FSK for signalling, FDM

History - 2nd Generation (2G) Systems (1991 4)(1991-4)

Systems:- 1991 First Group Special Mobile (GSM) network, Finland- 1992 Commercial GSM, all major European operators- 1992 Japanese Digital Cellular (JDC) system- 1993 GSM1800 system in commercial operation, UKy p ,- 1994 Commercial operation of D-AMPS (IS-54), US - U.S. Digital Cellular (USDC) and CDMA

• Technology: TDMA, TDMA hybrid FDMATechnology: TDMA, TDMA hybrid FDMA• Characteristics:

• Digital voice and low speed data• Frequency band @ 900 MHz, RF channel spacing 200 kHz• Modulation: GMSK, DPSK, Fixed frequency assignment• Speech rate 13 kbps, Speech coding, TDMA• High security and higher capacity, • Improved speech Quality of service (QoS)

1. NEC Cellstar 500 series (1992)2. Nokia 2110 series (1994)3 N ki 5120 (1998)• Improved speech Quality of service (QoS)

• GSM 1.8 GHz, and 1.9 GHzUSDC 1 9 GH

3. Nokia 5120 (1998)4. Kyocera 2135 (2002)5. Audiovox CDM8300 (2002)6. Samsung SCH-A650 (2004)

Prof. Z. Ghssemlooy

• USDC 1.9 GHz• Digital Cordless Systems (DCS) 1.8 GHz

Current - 3rd Generation (3G) Systems (1995 )(1995 - )

Support Multimedia Services:– Especially Internet Service, 144kb/s (Outdoor and higher velocity ), – 384kb/s(from outdoor to indoor) and 2Mb/s (indoor); – Speech of QoS and other services

First Transitional System: 2 GHz2000 - 2nd Transitional Systems: 2.5 GHz2001 1st CDMA Network @ 144 k bps2001 - 1st CDMA Network @ 144 k bps2002- Handover between GSM and WCDMA by Nokia and Vodafone2003 World's 1st IPv6 over 3G UMTS/WCDMA network, Ericsson ,2003 World's 1st CDMA2000 high-speed packet data phone call ( 3.09 Mbps), Nokia2004 World's 1st Enhanced Datarate for Global Evolution2004, World's 1st Enhanced Datarate for Global Evolution EDGE-WCDMA 3G packet data handover, Nokia and TeliaSonera2005, 9 Mbps with WCDMA, HSDPA phase 2, Ericsson

Prof. Z. Ghssemlooy

, p , p ,2005, 1.5 Mbps enhanced uplink WCDMA system, Ericsson

Current - 3G Systemsy

Are referred to as:Are referred to as:Universal Mobile Telecommunications System (UMTS) in Europe International Mobile Telecommunications 2000 (IMT2000) worldwide.

“UMTS will be a mobile communications system that can offer significant user benefits including high-quality wireless multimedia services to a convergent network of fixedmultimedia services to a convergent network of fixed, cellular and satellite components. It will deliver information directly to users and provide them with access to new and innovative services and applications It will offer mobileinnovative services and applications. It will offer mobile personalised communications to the mass market regardless of location, network and terminal used”.

Prof. Z. Ghssemlooy

UMTS Forum 1997

UMTS - Main Requirements (3 Ms)q ( )

Multi-media Multi-environmentM lti t Vi t l t

Multi-operator Virtual operators

Global Different environments for UMTS

Suburban Urban

Micro-Cell In- Building H C ll

Macro-Cell Pico-Cell

Home-Cell

Prof. Z. Ghssemlooy

H. Aghvami, KCL,UK

Mobile Telephony Standardsp y

A C P id Wh t’ Will P idAccess Standard

Company Provides What’s Coming

Will Provide

CDMA / TIA Verizon Voice, Data, 1XEV-DO 300-500 kbps, to 95 PTT, 1xRTT CDMA-2000 2.4 Mbps

TDMA / TIA 136

Cingular / AT&T

Voice, Data Edge 384 kbps data136 AT&T

CDMA / PCS Sprint Voice, Data 1XEV-DV to 3.1 Mbps

TDMA / iDEN Nextel Voice, Data, PTT

Spectrum change

Address public safety concern

GSM T-Mobile Voice Data GPRS W- 115 kbps dataGSM T Mobile, AT&T

Voice, Data GPRS, WCDMA, PTT

115 kbps data

Prof. Z. Ghssemlooy Source: IEEE

Technologies - Multimedia Messaging Service (MMS)Service (MMS)

It d d iIt d d iIt send and receives:–Text messages

Graphics and Photos

It send and receives:–Text messages

Graphics and Photos–Graphics and Photos–Audio, video clips–Graphics and Photos–Audio, video clips

MultimediaIt supports:

–Image: GIF, JPEG,It supports:

–Image: GIF, JPEG,

MultimediaMessaging

Service Image: GIF, JPEG, –Video: MPEG4–Audio: MP3, MIDI

Image: GIF, JPEG, –Video: MPEG4–Audio: MP3, MIDI

Service(MMS)

For high transmission speed uses:3G

For high transmission speed uses:3G

Prof. Z. Ghssemlooy

- 3G- GPRS: General Packet Radio Service- 3G- GPRS: General Packet Radio Service

Technologies - General Packet Radio Service (GPRS)Service (GPRS)

Packet based: – subs are always on line– easy and quick accessy q

Provide high speed wireless Internet and data communicationscommunicationsSpeed four times higher than conventional GSM systemssystems

Prof. Z. Ghssemlooy

Technologies - Bluetoothg

Short range RF technologyA global standardNo wiringData and voice communicationsOffers ad hoc network and synchronicity between all personal devicespersonal devices

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Mobile Computingp g

Applications

Interface Consider

ations

Communications, Connectivity and

Network Infrastructure

UsabilityIssues

Systems

Data Repositories/

Infrastructure

Persistent Storage

Prof. Z. Ghssemlooy

Systems Integration Database

Systems

Persistent Storage Media

Number of mobile phone subscribers in UKUK

http://www.mobilemastinfo.com/information/history.htm

Prof. Z. Ghssemlooy

Mobile Internet OutlookMillions1,400

Projectedcellular1,400

1,200 More handsets than PCs

cellularsubscribers(Nokia 1999)

1,000connected to the Internet by the

end of 2003 !Projected Web800

600

Projected Webhandsets(Nokia 1999)

400 Projected PCsconnected tothe Internet

200

0

the Internet(Dataquest 10/98)

Prof. Z. Ghssemlooy 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

0

Mobile Network in UK

5 network operators

45,000 base station sites. 2/3 i t ll d i ti b ildi t t2/3 are installed on existing buildings or structures.

< 2% are mounted on schools.

Additional mobile phone base stations will need to be built to support 3G services. It is possible that the number of base station sites will rise to 50,000 by

Prof. Z. Ghssemlooy

2007.

Mobile Communications - Definition

Designed to operate over a very large area with aDesigned to operate over a very large area with a limited bandwidth A cellular mobile comms system uses a large numberA cellular mobile comms. system uses a large numberof low-power wireless transmitters (100 W oe less)

Off l it th h ll littiOffers larger capacity through cell splitting Variable power levels allow cells to be sized according to subscriber density& demand within a particular region

As mobile users travel from cell to cell theirAs mobile users travel from cell to cell, their conversations are handed off between cells

Channels (frequencies) used in one cell can be reused

Prof. Z. Ghssemlooy

in another cell some distance away

Mobile Communications - Principlesp

Wave propagation mechanism is closely affected by the wavelengths of the propagating frequencyUses a separate radio channel to talk to the cell siteC ll it t lk t bil t iCell site talks to many mobiles at once, using one channel per mobile

Channels use a pair of frequencies for:• forward link for transmitting from the cell site

li k f th ll it t i ll f th• reverse link for the cell site to receive calls from the users

Radio energy dissipates over distance so mobiles mustRadio energy dissipates over distance, so mobiles must stay near the base station to maintain communicationsBasic structure of mobile networks includes telephone

Prof. Z. Ghssemlooy

psystems and radio services

Mobile Communs. - Cellular Spectrum

Phone Transmit

A band10 MHz

B band10 MHz

825 835 845824 846.5 849

A” b

A’ b

B’ b

333 channels30kHz

333 channels30kHz

band

and

and

1 MHz 1.5 MHz 2.5 MHz33 chs 50 chan 83 chs

20 MHz Guard

870 880 890869

A band B band

Base Transmit891.5 894

A A band10 MHz

333 channels30kHz

B band10 MHz

333 channels30kHz

A” band

A’ band

B’ band

Prof. Z. Ghssemlooy

1 MHz33 chan

1.5 MHz50 chs

2.5 MHz83 chs

Mobile Comms. - Systemy

• Mobile Unit• Mobile Base Station• Mobile Switching Centre

Prof. Z. Ghssemlooy

Mobile telecommunicationsswitching office (MTSO)

Mobile Comms. - Componentsp

Mobile Base Station (MBS): includesMobile Base Station (MBS): – includes – an antenna, – a controller,a controller, – a number of receivers

Mobile telecommunications switching office (MTSO)– connects calls between mobile units

Channels between mobile unit and MBSC t l h l t h i f ti l t d t tti– Control channels: to exchange information related to setting up and maintaining calls

– Traffic channels: to carry voice or data connection between yusers

Prof. Z. Ghssemlooy

MTSO Controlled Call between Mobile UsersUsers

Steps:-Steps:-Mobile unit initializationMobile originated callMobile-originated callPagingC ll t dCall acceptedOngoing callH d ff

Functions:-Handoff Call blocking

Call terminationCall droppingCalls to/from fixed and remote

Prof. Z. Ghssemlooy

mobile subscriber

Mobile Radio Environment

P ti P th LPropagation Path LossMultipath FadingFrequency-Selective FadingDoppler ShiftppCo-Channel InterferenceAdjacent Channel InterferenceAdjacent Channel InterferenceMan-Made NoiseUrban EnvironmentUrban EnvironmentSuburban EnvironmentR l E i t

Prof. Z. Ghssemlooy

Rural Environment

System Characteristicsy

Frequency sharing amongst users

M lti th i t f i tMultipath interference environment

Line-of sight coverage (UHF)

High base station antenna (30m)

Low mobile antenna (1 5m - 3m)Low mobile antenna (1.5m - 3m)

Beyond Line-of-sight (VHF)

Long distance (HF)

Prof. Z. Ghssemlooy

Early Mobile Systemsy y

Traditional mobile similar to TV broadcastingTraditional mobile similar to TV broadcasting

One very powerful transmitter y plocated at the highest spot would cover an area with a

di f t 50 kradius of up to 50 km

Cellular concept re-structured the mobile telephone network in a different way:network in a different way:

• Using low power transmitters to cover larger area. E g dividing a metropolitan region into 100 different cells

Prof. Z. Ghssemlooy

E.g. dividing a metropolitan region into 100 different cells 12 channels each

Digital Cellular- what does it offers?g

Best quality compared with analogue system

Improved bandwidth efficiencyImproved bandwidth efficiency- Reduced from 30 kHz to 10 kHz, and then to 5 kHz.

This is achieved via 3-time-slot Time Division Multiple Access (TDMA) (i.e. three pairs of people using a 30 kHz radio channel simultaneously)

Use of micro-cellular technology to accommodate smaller and smaller cells particularly around the new frequency band

f 2 GHof 2 GHz

Improved frequency reuse

Prof. Z. Ghssemlooy

Improved frequency reuse

Transmission Typesyp

f

Simplex

f1

f2

f1Tx : f1

Rx : f

f1

f2Rx : f2

Tx Rxf f

Tx : f1Rx : f2

Tx Rx

f2 f1 2

Half Duplex

Prof. Z. Ghssemlooy

Tx : f1, Rx : f1f1 f1

Transmission Types - Full Duplexyp p

f1 f3

f fTx : f1R f

Tx : f3R f

f4f3f2f1

f2 f4Rx : f2 Rx : f4

RxTx

TxRx

Prof. Z. Ghssemlooy

Transmission - Duplex Operationp p

f1 f2RxRx((ff )) Antenna

f1 f2

F((ff11))

DupDup

AntennaF1

TxTx((ff ))MM

f2((ff22))

T LoadTx LoadReception

Tx Load

Prof. Z. Ghssemlooy RxAntenna Transmission RxAntenna

Typical Wide-Area Systemyp y

DispatcherDispatcher

Di it l

Dispatcher2

DigitalSwitch

DispatcherDispatcher11

-- Dispatcher: Communicates with the vehicles.Dispatcher: Communicates with the vehicles.C i ti d H lf D lC i ti d H lf D l

Prof. Z. Ghssemlooy

-- Communication mode: Half Duplex.Communication mode: Half Duplex.-- MobileMobile--toto--mobile communication is possible using a Talkmobile communication is possible using a Talk--Through Repeater (halfThrough Repeater (half--duplex) or duplex) or direct using Simplex mode.direct using Simplex mode.

Mobile Transmission Environment

Deep Radio Shadow + Radio HorizonDeep Radio Shadow + Radio HorizonReflection, Refraction and ScatteringFadingFading– Frequency-Selective– Multipath

Propagation Path Loss (Attenuation)Doppler ShiftDelay DistortionyNoise and InterferenceUrban Suburban and Rural Environments

Prof. Z. Ghssemlooy

Urban, Suburban, and Rural Environments

Transm. Pro. - Deep Radio Shadowp

Radio waves at low frequencies can diffract (bend) around object quit• Radio waves at low frequencies can diffract (bend) around object quit well

• In mobile systems (high frequency band), wave diffraction does not take place well, therefore a deep radio shadow occurs on the un-illuminated side of the obstruction (e.g., building, hill, truck, or even human being)

shadow

human being)

shadow

T

Prof. Z. Ghssemlooy

Tx

Transm. Env. - Radio Horizon (1/2)

• Is 30% farther from the transmitting antenna than the equivalent visible horizon due to the reduction of the refraction in the upper atmosphere as compared to that

t d l lat ground level.

Beyond radio horizon the signal strength falls very rapidlyBeyond radio horizon, the signal strength falls very rapidly so that in areas well beyond the horizon the same frequency

can be reused without causing interference.g

• The higher the transmitter antenna the further away isThe higher the transmitter antenna, the further away is its radio horizon.

Prof. Z. Ghssemlooy

Transm. Env. - Radio Horizon (2/2)

The coverage area (not the radius) is approximately proportional to the antenna heights of both transmitter and receiverand receiver.

With a higher transmitter tower the far flung horizonWith a higher transmitter tower, the far flung horizon prevents close reuse of the same frequency.Between the transmitter and horizon in open flatBetween the transmitter and horizon, in open, flat country, the received power reduces approximately as the inverse fourth power of distance from the transmitter (as we see later on).

Prof. Z. Ghssemlooy

Transmission Env. – contd.

Ei

Reflection at large obstacles

i

Er= α Ei, where α is the absorption coefficient < 1

Ei

Scattering at small obstacles Er1= α Ei

E 2= α EiEr2 α EiErk= α Ei

E 1= α E

Diffraction at edges

EiEr1 α Ei

Er2= α Ei

Prof. Z. Ghssemlooy

Diffraction at edges

Transm Env – MultipathTransm. Env. – Multipath

Dispersion

signal at Tx

Dispersion

Distortion

signal at Tx

signal at receiver

Dispersion: signal is dispersed over time, thus interfering with “neighbor” symbols --> Inter Symbol InterferenceDistortion: signal reaches a receiver directly and phase shifted:- distorted signal depending on the phases of the different parts

Prof. Z. Ghssemlooy

different parts

Transm. Pro. – Multipath Fadingp g

In a multipath propagation environment signal are:In a multipath propagation environment signal are:

- Generally added to strengthen the received signal- At some point they subtract from one another, thus causing

fading, (at approximately half wavelength intervals).- The fade power level is typically 20 dB weaker than the local

average field strength. Fades that are 40 dB weaker are not uncommon.

- The combination of shadowing and multipath fading resultsin a radio field that varies wildly over a short ranges (up to 60 or 70 dB difference between the maximum and minimum t t l l l ithi 100 2)

Prof. Z. Ghssemlooy

street level value within a 100 m2).

Transm. Env. - Attenuation

• The strength (amplitude) of the signals reduces as it• The strength (amplitude) of the signals reduces as it propagate through the channel. This is called signal attenuation or loss, which is due to:,• Absorption of energy• Scattering of energy

• Limits the maximum coverage distance. • Can be overcome by in line amplification.Can be overcome by in line amplification.

High frequencies penetrates building fairly well, mostly th h d i d d thi t lli f

High frequencies penetrates building fairly well, mostly th h d i d d thi t lli fthrough doors, windows, and thin non-metallic roofs.

Typical mean building penetration losses are 10 to 20 dB, but penetration losses as high as 40 dB have been

through doors, windows, and thin non-metallic roofs. Typical mean building penetration losses are 10 to 20 dB, but penetration losses as high as 40 dB have been

Prof. Z. Ghssemlooy

dB, but penetration losses as high as 40 dB have been encountered.

dB, but penetration losses as high as 40 dB have been encountered.

Transm. Env. - Bandwidth

• All real channels have a limited bandwidthAll real channels have a limited bandwidth.

• Not all the frequency components of transmitted signal will pass through the channel.

• At the receiver, exact regeneration of the original signalAt the receiver, exact regeneration of the original signal becomes quite difficult.

• Resulting in the received signal distortion• Resulting in the received signal distortion

Prof. Z. Ghssemlooy

Transm. Pro. - Delay Distortiony

• Critical in complex waveform transmission, such as Digital Signals, where different frequency components of the same signal travel at slightly different speedssame signal travel at slightly different speeds.

• As the propagation link increases, fast components of one bit (edges) may eventually catch up the proceeding slow ( g ) y y p p gmoving components of the bit (flat top). Thus resulting in distortion.

Prof. Z. Ghssemlooy

Transm. Pro. - Noise & Interference

. Thermal noise

. Amplifier noiseRF

RF + NoiseReceiverReceiver

RF signal

. Man made noise

. Inter-modulation: noise from other transmitters at different frequencies

. Co-channel interference: noise from other transmitter at the same frequency

Prof. Z. Ghssemlooy

frequency . Electromagnetic interference in a vehicle

Mobile Phones Technology -DisadvantagesDisadvantagesAlthough the development of mobile phones brought convenient andAlthough the development of mobile phones brought convenient and

advantages to the world. But the disadvantages brought along with the fast grown technology cannot be ignored. These problems not only influenced people personally but also the society at largeonly influenced people personally but also the society at large. Symptoms caused by the radiation of mobile phones are:– headache, earaches, blurring of vision and even causing cancer

Though, these problems are still under research. Mobile phone users are advice to reduce the usage on mobile phones if it is possible. p

Mobile phone addiction. – Mobile phone addiction is becoming one of the biggest non-drug

addictions in the 21st century in particular among the teenagersaddictions in the 21st century in particular among the teenagers.– New models of mobile phones are released almost everyday. In order

to get up-to-date, people tend to change their mobile phones once in a while These became habits among the mobile phone users causing

Prof. Z. Ghssemlooy

a while. These became habits among the mobile phone users causing them to spend unnecessary cost on mobile bills and

Mobile Phone Technology - Future DevelopmentDevelopment

Mobile phones are getting more and more sophisticatedMobile phones are getting more and more sophisticated, just like computerThe technology is growing everyday with different functions and usageFrom the network system from mobile phones, it is still developingdeveloping. – The new 3G system had just been launched not long ago, – 4G system expected in 2010. It is expected that the 4G

system will be able to deliver• a much faster speed up to 100Mb per second during connection,• tighter network security • High quality during communication no matter on voice or video calls.• security system, and surveillance on certain items. The 4G system will be

expected to be launched in 2010.

Prof. Z. Ghssemlooy

Mobile Phone Technology - Future DevelopmentDevelopment

Mobile phone, the piece of communication device itself is also becoming a multi functioned device. S t h d PDA h l dSmartphones and PDA phones are already launched in the market. M bil h ith ti f ti l iMobile phone with computing functions replacing lap-tops

Prof. Z. Ghssemlooy

Summaryy

HistoryMobile technologiesPrincipleCharacteristicsTransmission properties

Prof. Z. Ghssemlooy

Next Lecture

Cellular ConceptCellular Concept

Prof. Z. Ghssemlooy